OLEORESIN PRODUCTION. 7 



It is both from the horizontally extended fusiform rays, as ex- 

 posed on a freshly cut tangential surface, and the vertically extended 

 parenchyma aggregates, as exposed on the cross section, at the streak, 

 that the droplets of oleoresin may be seen to exude. Large nuclei 

 are often to be seen in these cells, as well as accumulations of starch 

 grains. Tannin is also reported to be associated with resin forma- 

 tion. 12 The vertical and horizontal systems of resin-producing 

 parenchyma are more or less united, since they frequently cross 

 each other. The method of turpentining which keeps these cells 

 active and which provides suitable stimulation to insure their great- 

 est productivity without undue injury will give the highest and best 

 yield of oleoresin over a period of years. In the discussion in the 

 following pages of the results from the experiments, the methods 

 used were judged, not alone by the yield obtained, but also by the 

 amount and type of the wood tissue produced, as indicative of the 

 vitality and responsive power of the trees. In each case the wood 

 tissue produced by neighboring, comparable, unturpentined trees 

 growing under similar environment was studied and used as a check 

 upon the judgments formed. 



METHODS OF STUDY. 



COLLECTION AND TREATMENT OF MATERIAL. 



The first material to be studied was in the form of fresh chips or 

 pieces collected by the writer from the living trees and put in corked 

 bottles. This material was examined within a few hours after cut- 

 ting. Specimens shipped to the laboratory at Madison periodically 

 during the season were handled in the same way, with the exception 

 that sometimes moistened cotton was put in the bottles to prevent the 

 drying out of the specimens. Later, fixing solutions were used, and 

 the chips or increment borings were placed in the solution selected as 

 soon as cut. These were kept for a length of time which necessarily 

 varied with circumstances, washed with water, and stored in glycerine 

 and alcohol. The fixatives used were: (1) Mercuric chloride, a satu- 

 rated solution in 90 per cent alcohol; (2) mixture of a saturated 

 solution in 90 per cent alcohol of mercuric chloride (3 parts) and of 

 picric acid (1 part) ; (3) chrome-acetic fixative, consisting of a mix- 

 tun', in LOO cubic centimeters of water, of 1 per cent glacial acetic 

 acid and 0.7 \><-r cent chromic acid. 



u •!- and mil: "Introduction to the Chemistry <>f Pldnl Products," Fol. i, .'id K<i. 



UtJl pp. 195,217. " In finim U lygtated that the amount of lannin varies will) thai of 

 thf rf.xln : thus In tbe Spring It wan found thai as the tannin decreased In amount so (he 



n Increased. ♦ • • That starch frequently is contained In the same cells with tannin 

 suggest a connection between tbe two and it is not Impossible that, the starch may con 

 tribute glucose for the con tftatfon "f the tannin. The ••'•lis surrounding the epithelium 

 of re in ducts contain tannin and starch." Wiener " oic Rohstoffe des PflanzenreJ 



concluded thai, tannin was an Intermediate product iu renin formation. 



